start qpdfview from cmd line with:
qpdfview >out.txt , then open a pdf file and close the app again.
qpdfview 2>out2.txt , then open a pdf file and close the app again.
see if one of the files contains some info.

please show me your libpath of config.sys. and tell me where you installed the additional dll as mentioned in the install.os2. as there must be a conflict of some dll's somewhere.
and no it's not qpdfview.dll which is not found, but a dll needed by qpdfview.dll can't be loaded.